Mr Trump has achieved what everyone said was inconceivable. From the moment he announced his candidacy, he was branded a clown, a demagogue and a blowhard articulating the frustrations of disgruntled groups. He proved the pundits wrong. Tellingly, few who predicted his inevitable implosion are now prepared to rule out the possibility that he might win the presidency itself.

The billionaire property dealer has got this far on the basis of the support of a tiny proportion of the US electorate that voted in the primaries. Whether he can pull together a much broader coalition to win nationwide cannot be discounted, since Mrs Clinton approaches the final stages of this interminable race laden with baggage from her husband’s time in office and her own record as a senator and secretary of state.

Every presidential election is billed in advance as a “contest like no other”. But this one truly will be. Mr Trump, a former Democrat, fits no orthodox political model. He is like an independent who has captured one of the two great parties and can now rely on its organisation to propel him to an unlikely triumph. The Cleveland convention cannot disguise that some dissent still exists within the Republican Party to the Trump candidacy. But they have nominated him now and will campaign for their man. They said Candidate Trump was unthinkable. President Trump no longer is.